Traffic signal



April'ZS, 1942. L A CLARK 2,281,139

TRAFFIC SIGNAL Filed April 24, 1941 2 Sheets-Sheet l 'April 28, l942- L. Ae CLARK 2,281,139

TRAFFIC SIGNAL Filed April 24, 1941 2 Sheets-Sheet 2 Patented Apr. 28, 1942 UNITED STATES IPATENT OFFICE 10 Claims.

This invention relates to traffic signalling systems, and more particularly to a very simple and economical circuit making and breaking mechanism for controlling traffic lights and to a new arrangement of wiring by virtue of which the likelihood of getting the various lights wholly out of synchronisrn, or the likelihood of the short-circuiting of any of the lights under attempts of inexperienced persons to adjust the timing of the same, will be prevented. This application is a continuation in part of my application, Serial Number 256,637, led April 7, 1939, which became Patent No. 2,243,088.

A further object of the invention is to provide a simple manual control for the mechanism.

A further object of the invention is to provide means for effecting a flashing of the caution signal, if desired- A further object of the invention is to provide a the green light, fol` example, may be caused to serve both as a caution and as a go light by causing it to show as a steady light duringthe go period and to flash through the caution period as an indication that the red or stop signal is about to flash on.

Embodiments of the invention by virtue of which I accomplish the foregoing objects are illustrated in the accompanying drawings, where- 1n:

Figure 1 is a plan view of the timing mechanism of the invention;

Fig. 2 is a front elevation of said timing mechanism;

Fig. 3 is an end elevation of the timing mechanism;

Fig. 4 is a fragmentary view of one of the toothed disks hereinafter described;

Fig. 5 is a perspective View of one of the mercury switches, its holder and operating shaft;

Fig. 6 is a detail view of a means for varably setting the trips or tappets of the disks to varying positions with respect to each other;

Fig. 7 is a diagrammatic view of one form of wiring in which no ashing of the caution light takes place;

Fig. 8 is a diagrammatic view of the wiring and mechanism used when the caution light is a flashing light;

Fig. 9 is a form of Wiring and mechanism used when the green light is caused to function both as a caution and go signal;

Fig. 1'0 is a detail view partly in section of the manual control elements, and,

- A synchronous motor 1, such as is commonly employed in the driving of electric clocks, drives through gears 8, 8a to a sleeve 88 that is loosely mounted on a main drive shaft 9. Shaft 9 has a block Siti fixed upon its end. This block has a keyhole 9| formed in it for the reception of a manual control key 92. A dog 93 is pivoted at 94'l in and upon the block and the end of said dog projects beyond the inner end of the block to be engaged by the shoulder of a notch 95a of a disk 95. This disk is fixed upon the outer end of sleeve 88. As long as the dog lies in positionV to be engaged by said notch, the turning of sleeve S8 by the motor acts to turn shaft 9 through block 9D. When it is desired to control the signal manually, the key 92 is thrust into the block to engage the dog at 96 and lift the end of the dog enough to free it of the notch of disk 95. Shaft 9 is thereupon freed from the motor and may be rocked back and forth to manually control the lights, through key 92.

The motor, when in action, serves to drive shaft 9 at a uniform and determined rate of speed, as for example, one revolution per minute.

Shaft 9 is suitably suported in bearings I0. A sleeve I I is mounted to turn with respect to shaft 9. This sleeve carries disks I2 and I3, said disks being fixed to the sleeve so that they are forced to turn together. The shaft 9 has a pair of disks It` and I5 pinned or otherwise secured thereto, sc that they are forced to turn with the'shaft.

Disk I3 carries a trip arm I6, and diskl I4 carries' a trip arm Il.

These trips act as the disks rotate to thrust in one direction or the other against one tip or the other of a triangular plate I8 that is mounted upon the end of a shaft I9 (Fig. 5). is journaled in a sleeve I9b of block 6 and carries a clip 20 at its outer end that is adapted to receive the glass tube forming the body portion of a conventional mercury switch, saidv switch constituting the master switch 35, hereinafter described.

As the disks I3 and I4 rotate, the tripsact to rock the shaft I9 first in one direction and then in the other. This tips the tube 35 of the master mercury switch.

The structure described is duplicated with re- Shaft I9' spect to additional mercury switches 31 and 38, and the same reference characters have been applied. The rock shafts ISL-|91 of the switches 31 and 38 carry triangular plates IBL-|81. The plate I8a is engaged and moved in one direction by a trip arm and in the other direction by a trip arm 2l. Trip arm 2li is carried by disk I2 and trip arm 2l is carried by a disk I2a that is loose on shaft 9 and may be held in any desired angular relation to disk I2 through the medium of a pin 22 which is carried by a spring plate 23 fixed to disk I2a and is adapted to engage any one of the teeth I2b of disk I2. (See Fig. 6). A corresponding spring plate 23a provides for angularly setting the trip I6 with respect to trip I1.

In like manner, plate ISb is moved by a trip arm 214 on disk I5 and by a trip arm 25 of a disk 26. Disk 26 is loose on shaft 9 and is held in any desired angular relation to disk I5 by a pin 22 on spring arm 28. Arm 28 is secured to the face of disk I5 and may be sprung away from said disk far enough to disengage pin 22 from the teeth 26a of disk 26 when it is desired to adjust theyangular relation of trip arms 2t and 25, to, in turn, determine the interval of time which shall elapse between the time of tilting the mercury switch 38 in one direction and the time of tilting said switch in the opposite direction.

I have illustrated that thedisks I2, I4 and 25 are toothed disks and in Fig. 4 I have indicated that the disks may have their notches numbered with numerals a from one to sixty, indicative of seconds. The positioning of the trip arms It and I1 determines the time of change between the N-S red light and the E-W red light; while the positioning of the trip arms 2t, ZI; 24, 25, determines the period through which the amber light will show before the green light comes on.

The manner in which this is accomplished may easily be understood by referring to Fig. '7. In this gure, 52 indicates a conductor constituting a source of incoming current. The mercury switches that I employ, while being of a conven tional type, differ from simple circuit closers in that'they complete one circuit when tipped in one direction and complete another circuit when tipped in another direction.

For example, when 35 is tipped to the right, a circuit is completed at b through the contact bar c of the mercury switch to conductor 53. This conductor is connected to the contact bar d of the mercury tube 38, but at a point ahead of said mercury tube 38, a conductor 54 connects 53 with the N-S red light 55. When the tube 5 is tipped in the opposite direction, arcircuit is completed at e between contact bar c and a conductorv which leads to the contact bar f of mercury tube 31. However, at a point ahead of mercury tube 31, a conductor 5l' leads from 5t to the E-W red light 58. I

Thus it will be seen that the tube 35, which constitutes the master switch, controls the two red lights under the influence of the setting of the two completeY units I2, I3 and I4, I, and that this control of the red lights which determines the duration of the complete cycle of operation of the switch is independent of theL period of dwell between the amber and green lights of the N-S, E-W sides of the signal, this duration being determined by the time of tipping of 31 and 38. l

With tube 3S in the position illustrated in Fig. '7, a circuit is completed at g through conductor 59 to the .T l-W green light Si). With tube tt tipped in the opposite'vdirection, a circuit will be completed at h through a conductor 6I to the amber light 62 of the E-W side of the signal. In like manner, with the tube 31 tipped to the position illustrated in Fig. 7, a circuit is completed at i through a conductor E3 to the amber light of the N-S side of the signal. When tube 31 is tipped in the opposite direction, a circuit will be completed at'y' through a conductor t5 to the green light 66 of the N-Sv side of the signal.

In Fig. 3 I have illustrated a feature which may be employed or may be omitted, since the remainder of the structure will operate with or without it. In this feature, I have illustrated a disk 13, graduated as indicated at Ill after the manner of a clock dial and provided with sixty graduations. A pointer or hand i5 is carried by a pin 1t, which projects from the end of the shaft 9, and thus the movement of the hand is in unison with shaft 9.

This facilitates the work of the officer charged with synchronizing lights at different intersections, because with the second hand of his watch set in synchronism with the hand 15, he can, if the disk 'It and hand 15 be exposed to view, drive along the street and at a glance determine just how much any given signal is out of synchronism with its fellows.

I am aware of the fact that it is quite old in the art to provide circuit closers embodying a plurality of contact making and breaking members, and even to use tipping mercury switches in conjunction therewith. I-Iowever, I do not know of any mechanism embodying such extreme simplicity as that disclosed in this application or embodying the master switch controlling the relation of the N-S cycle with respect to the E-W cycle while leaving such master switch wholly free oi' accidental short-circuiting due to the effort of any person to adjust the auxiliary switches controlling the amber and green lights of the N-S side of the signal, upon the one handand the E-W side of the signal upon the other. It will be very clear that nothing that an inexperienced person might do in endeavoring to adjust the relationship of the amber and green lights could bring about any disorganization of the main cycle of operation.

In those traffic signals having a plurality of switches all of equal value, one of which controis one red light, another of which control the other red light, another of which controls one green light, another of which controls the other green light, another of which controls one amber, and another of which controls the other amber light, all of said switches being independently adjustable, it is very easy to get the Various lights so mixed up that it is almost impossible to straighten them out. In an endeavor to do so, the inexperienced person frequently connects two positives tothe same light, resulting in shortcircuiting the lights, burning them out, and bringing about confusion in trai-lic. Nothing of this sort can happen with the signal oi" the present invention.

In Fig. 8 the arrangement differs from that shown in Fig. 7 in the following respects: A

motor lVi is connected by a connecting rod IUD with a tiltable mercury switch lill, and as the motor rotates, the tube of this switch is rocked back andforth. Two wires or connectors |02, |03, are arranged to be connected by the mercury in the switch, when the latter is in its intermediate position, and thustwo connections are made for each rotationA of the motor M. A relay magnet |64 is arranged to attract an armature |05' in one direction, said armature being movedin the opposite direction by a spring |06.

Thewire |03 of the flasher is connected to a contact point |01 arranged to be engaged by the armature, when said armature is attracted by the magnet. This wire is also connected to contact point arranged to be engaged by the armaturewhen the armatureis moved away from the magnet by the spring |05. When in the latterv position, |08 is connected by the armature with a contact point |09, the latter, in turn, being connected by a conductor Gla with the E-W caution light 52. When the armature is attracted by the magnet, it bridges the space between and connects contact i0? with a contact point H0. This contact point is connected by a conductor 53a with the N-S caution light E4,

The left-hand contact of the mercury switch t0 is connected by a conductor ll'l with the motorr M, With the parts in the position illustrated in Fig. 8, the E-W go light 60 receives current as previously described from 52, 5?,l 38 and 59. The next movement is a shifting of switch 38 which takes place before any movement of switch 35. When this happens, the mercury travels to the left-hand end of the tube of switch 33, extinguishing go light 60 and energizing caution light 52 through the flasher. The wire im is connected to the conductor 5t and is also connected through a shunt |0221E with the conductor lil. When the tube of switch 38 is tipped to the left, the hashing motor M is energized.

The connection to the E-W flashing light |52 at this time is as follows: From positive conductors 52, through 53, |022 |02, |03, contacts |03, |535) and conductor Gla. The next operation is when the tube of master switch tips downwardly toward the left. This lights the Ef-W red light 58 from 52, through '56 and 51. It also lights the N-S green light from 52, through 56 and switch 3l, the latter at this time being tipped downwardly toward the left to establish connection with conductor E53. This condition continues until the switch 31 tips downwardly toward the right to extinguish the go light E6 and light the caution light 64.

When the tube of switch 31 tips downwardly toward the right as described, the motor M is energized with current from 52, through 56, switch 3l, conductor H2. Current is also supplied through conductor H3 to the winding of magnet |011, thus attracting the armature |05 against the action of spring |06. Caution light 64 is then caused to ash lby current from 52, through 56, |02, |63, |01, I|0 and 63a. It will be observed that at this time, the connection |02El has no eiect upon any of the lights because the tipping of 33 to the left broke the connection to conductor 50.

In the modification ilhmtrated in Fig. 9, the arrangement is substantially the same except that the go light also serves as the caution light, being connected in one position of switch 31 to burn steadily with current from 52, and being connected in the other position of said tube with 52 through the flasher.

While the machine that I have devised for accomplishing the foregoing results, and which I have illustrated herein, has been found to be highiy efficient in actual tests and is very economical of construction and certain in operation, I wish it to be understood that the invention is not limited to this particular mechanism. It is clear that the skilled engineer may und other in, (A)

ways of utilizing the principles of the invention through mechanism of another type.A Therefore, it is tobe understood that the invention includes within. its purviewwhatever changesfairly come within either the terms or the spirit of the appendedlclaims.

Having described my invention, what I claim is:

1. In a traic control mechanism, the combination with a double throw master switch and a pair. ofV auxiliary double throw switches, of a motor, a first rotative part driven by said motor, alsecond rotative part mounted to turn with but adjustable upon the first rotative part, means for holding said parts in locked position and in varying positions of circumferential adjustment with respect to each other, an actuating member uponthe said first rotative part for throwing the master switch in one direction, an actuating member upon said second rotative part forl throwing the master switch in the other direction, actuating means carried wholly by the first rotative part arranged to engage and move one of the auxiliary switches first in one direction and then in the other in the rotation of said part, and actuating means carried wholly by the second rotative part for moving the other auxiliary switch rst in one direction and then in the other in the rotation of said second rotative part.

2. A structure as recited in claim 1, in combination with a manual control member and means under control of said member for disconnecting the first rotative part from the motor and means through which said first rotative part may be manually actuated by said manual control member.

3. A structure as recited in claim l wherein the iirst rotative part comprises a shaft, a sleeve upon said shaft, gearing between the motor and sleeve by which continuous rotation is imparted to the sleeve, interengaging means between the sleeve and shaft and manually operable means for throwing said interengaging means out of action to free the shaft of the sleeve.

4. A structure as recited in claim l wherein the rst rotative part comprises a shaft, a sleeve upon said shaft, gearing between the sleeve and motor, a block having a keyhole in it fast upon the shaft, a notched disk upon the sleeve and a dog pivoted upon the block for engagement by the notched disk, said dog being shaped to be engaged by the key and to be moved out of engagement with the disk and the keyhole of the block being so shaped as to prevent rotation of the key therein, so that when the key is inserted in the block, the block and shaft may be manually manipulated by the key.

5. In a circuit controlling mechanism for traffic signals, a synchronous motor, a shaft driven by said motor, a pair of trip-carrying members xed to and rotating with said shaft, trips carried by said members, a sleeve loose on said shaft, a pair of trip-carrying members carried by said sleeve, trips on said members, means for holding the sleeve in varying positions of angular adjustment with respect to the shaft, a master switch actuated under control of one trip of the sleeve and of one trip of the shaft and a pair of auxiliary switches, one of which is actuated by a trip of the sleeve and the other of which is actuated by a trip of the shaft.

6. A structure as recited in claim 5 wherein the switches are oscillatory mercury switches, shafts upon which said switches are mounted and cranks upon said shafts disposed in the path of movement of the respective trips.

7. A structure as recited in claim 5 in combination with a, manual control member, movement of which in one direction disconnects the shaft from the motor, and movement of which in another direction turns the shaft to effect manual control of the structure.

8. A structure as recited in claim 5 in combination with a block upon said shaft constituting a part of the driving connection between the motor and the shaft, said block having a keyhole formed therein, a key adapted to enter said keyhole and a locking dog controlled by said key, said locking dog also constituting a part of the driving connection between the motor and the shaft, said locking dog being shaped to be disengaged when the key is inserted and to thereby leave the shaft 'under the manual control of the key.

9. In combination, a shaft carrying a pair of disks, a trip upon each of said disks, held in xed circumferential relation to each other by attachment of the disks to the shaft, a sleeve mounted to turn upon said shaft, a pair of disks carried by said sleeve, one of which lies substantially face to face with one of the disks of the shaft, a pair of trips carried by the disks of the sleeve and held in iXed circumferential relation to each other by the attachment of the disks of the sleeve to said sleeve, a latching mechanism between the abutting disks of the sleeve and shaft respectively, adapted to engage at a large number of positions circumferentially of the shaft, so that the sleeve may be locked to the shaft in a large number of varying circumferential positions, a master double throw switch, a part carried by the master switch disposed in position to be engaged by and to move the master switch in one direction under the iniluence of that trip of the shaft that is carried by the disk which lies in confronting relation to the disk of the sleeve, said part being moved to move the master switch in the opposite direction under the inuence of that trip that is carried by CTI the disk of the sleeve which lies in confronting relation to the disk of the shaft, and a pair of double throw auxiliary switches comprising actuating parts disposed in the path of movement of and adapted to be moved in one direction by the trips that are carried by the remaining disks of the sleeve and shaft respectively,

10. In combination, a shaft carrying a pair of disks, a trip upon each of said disks, held in fixed circumferential relation to each other by attachment of the disks to the shaft, a sleeve mo-unted to turn upon said shaft, a pair of disks carried by said sleeve, one of which lies substantially face to face with one of the disks of the shaft, a pair of trips carried by the disks of the sleeve and held in xed circumferential relation to each other by the attachment of the disks of the sleeve to said sleeve, a latching mechanism between the abutting disks of the sleeve and shaft respectively, adapted to engage at a large number of positions circumferentially of the shaft, so that the sleeve may be locked to the shaft in a large number of varying circumferential positions, a master double throw switch, a part carried by the master switch disposed in position to be engaged by and to move the master switch in one direction under the inuenceof that trip of the shaft that is carried by the disk which lies in confronting relation to the disk of the sleeve, said part being moved to move the master switch in the opposite direction underried b-y said members for moving the auxiliary switches in the other direction.

LEROY A. CLARK. 

